Electric Bike Mid Drive Guide

Mid drive systems provide motor power through the cranks of the bike to leverage the drivetrain (or “transmission”) to climb almost any hill and speed along on flat ground.

Mid drives have been popular in many European markets and they are starting to gain popularity in the US and Canadian markets.

This guide will outline the popular systems that are equipped on complete e-bikes as well as retrofit mid drive systems that can be added to a conventional bike.

For a list of pros and cons, here is an article that compares mid drives to hub motors and friction drives.

 

Mid Drives on Complete E-Bikes

Bosch

Bosch is the powerhouse brand in the mid drive market.  They are on many European e-bikes and they are currently working hard to establish themselves in the US market with a new office and service center.

They offer a number of systems with different power (250-350 watt), torque (50-60 Nm) and speed options (25 km/h to 45 km/h).  Bosch systems are pedal assist only and they use torque, cadence, and wheel speed sensors to provide the proportional assist.

The Bosch system integrates with automatic and/or electronic shifting systems from Shimano, SRAM, and NuVinci.

Examples of bikes that use the Bosch system: Haibike, Felt Electric, Easy Motion, Lapierre, Grace, KTM, Xtracycle, etc.

Markets: many European markets and the US.

 

Shimano STEPS

Shimano recently introduced their STEPS mid drive system that features a 250 watt pedal assist motor. The STEPS systems works with Shimano’s Di2 electronic shifting system and their Alfine 8 or 11 speed internally geared rear hub.  STEPS also works with traditional drivetrains (cogs & derailleur) or internally geared hubs.

Examples of bikes: Raleigh, and more to be announced soon.

Markets: many European markets and the US.

 

Impulse

The Impulse is a proprietary motor system for Derby Cycle that owns Kalkhoff, Focus, and Raleigh (Germany) brands. The Impulse system has a shift sensor technology, a belt drive option, and other customization options that make for a smooth ride.

Examples of bikes: Kalkhoff, Focus, and Raleigh (Germany).

Markets: many European markets and the US.

 

TransX

TransX currently makes 2 different style mid drive systems with power ranging from 250 to 425 watts and up to 63 Nm of torque.  They also have an automatic shifting system (AGT) and a new computer based diagnostic system (LogiX). TransX has also been busy setting up service centers in Europe.

Examples of bikes: IZIP and others.

Markets: many European markets and the US.

 

MPF

MPF offers a mid drive system with 250-500 watts of power, 40Nm of torque with a torque, cadence, and wheel speed sensor pedal assist system.  The MPF system can accommodate up to 3 chainrings.

Examples of bikes that use the MPF system: iGo, Butchers & Bicycles, Leaos, and more.

Available in the US and many European markets.

 

Panasonic

Panasonic has been making mid drive systems for a long time and they have been featured on many electric bikes.  It is a 250 watt mid drive torque sensing pedal assist system that has mainly been intended for the European and Japanese markets.

Examples of bikes: BH Easy Motion, Spencer Ivy.

Markets: Europe and Japan.

 

Yamaha

Yamaha has been in the e-bike business for a long time. In the past they mainly focused on the Japanese market but they recently introduced their new PW system for the European market.  It is a 250 watt motor with up to 80 Nm of toque and it uses a torque, cadence, wheel speed pedal assist sensing system. The Yamaha system also offers the ability to use 2 chainrings, instead of 1 chainring that is found on most mid drives.

Examples of bikes: Haibike Sduro series.

Markets: many European markets and Japan.

 

Sunstar

Sunstar offers the S03+ mid drive that comes on complete bikes and can be retrofit to many bikes. Sunstar recently introduced their new “quick release” Virtus system that can be installed or removed from a bike in minutes.  It features a double battery option, wireless connectivity, smartphone integration, and more. The Virtus system is a 250 watt 55Nm motor and it uses a torque, cadence, and wheel speed pedal assist system.

Examples of bikes: Sunstar bikes.

Markets: many European markets and Japan.

 

Bafang Max

Bafang recently introduced their Max mid drive system that features 250-350 watts of power with 80Nm of torque!  It looks like it initially will be targeted for the European market for both traditional pedelecs in addition to speed pedelecs (up to 45 km/h).

Examples of bikes: TBA.

Markets: many European markets and the US.

 

Continental

The Continental mid drive system features 250 watt of power with up to 50 Nm of torque. The system will be available using a normal chain (up to 2 chainrings are possible) or Continental’s belt drive.

Examples of bikes: A2B.

Markets: Initially it looks like the Continental system will be available on bikes in the European markets.

 

Optibike

Optibike has been making mid drive electric bikes for a long time.  They started with their original motorized bottom bracket (MBB) and now they have developed the SIMBB (shown above) that houses the motor, battery, and controller in the bottom bracket area.  Optibike offers a number of different power options that go up to 1,100 watts of power!

Examples of bikes: Optibike mid drives are currently only available on their own bikes.

Markets: The US. Check with Optibike for shipping to other markets.

 

Samsung

Samsung is rumored to be working on a complete mid drive system with some interesting features.

Examples of bikes: TBA

Markets: TBA

 

E2 Drives

This one of the more innovative designs that I have seen recently. The E2 Drives combine a mid drive motor with a mid gearbox and Gates belt drive. There is manual and automatic electronic shifting too. It is still in the developmental stages but hopefully we will see it on complete e-bikes soon.

Examples of bikes: TBA

Markets: TBA

 

E-Ram:

The E-Ram mid drive is claimed to be the lightest mid motor because it only adds ~1.1 kg (2.5 pounds) to the bike.  The motor is on the non drive side (left side) of the bike and the diameter is about the same as a middle chainring with 4cm (1.6″) of width. It fits a conventional bottom bracket and allows for many traditional rear suspension designs.  It is intended for electric mountain bikes. The battery can be stored in a backpack or hydration pack. Stay tuned for more specs and when this system will be available.

 

Mid Drive Kits for Converting a Conventional Bike

Bafang:

The Bafang BBS01/02 mid drive system is one of the more refined retrofit mid drive kits that is readily available.  It has power options ranging from 250, 350, 500, to 750 watts and up to 80 Nm of torque.  It uses a cadence sensor pedal assist system in addition to a throttle.

Markets: Europe and US.

 

Sunstar:

Sunstar makes the S03+ mid drive retrofit system with 250 watts of power and torque sensor pedal assist. They offer the kit as well as their own bikes with the kit installed.

Markets: many Europe markets.

 

Bikee Bike:

The Bikee Bike mid drive places the motor on the right side of the bottom bracket instead of in front like the Bafang and Sunstar. They offer 250, 500, and 750 watt versions with up to 150 Nm of torque!

Markets: many European markets and the US.

 

EcoSpeed:

EcoSpeed offers some powerful mid drives; 1,300+ watts! Their system can be customized to fit almost any kind of bike or trike. They are assembled in Portland, OR.

Markets: US and Canada and possibly more. Check with EcoSpeed.

 

Stoke Monkey:

The Stokemonkey mid drive kit is mainly intended for cargo bicycles.  This kit provides 500+ watts of power depending on what battery voltage you choose.

Markets: US and Canada and possibly more. Check with Ebikes.ca.

 

EGO-KITS:

The EGO Kits mid drive system are intended for off road bikes because they provide up to 3,400 watts of power! That is a lot of power.  The battery goes in your backpack or hydration pack.

Markets: many European markets and the US.

 

More Mid Drives

That is an overview of some of the more popular mid drive electric bike systems out there. ElectricBike.com has an extensive list of more DIY retrofit kits.

Stay tuned because there will be more mid drive systems coming to the market! I will be adding more systems to this guide.

P.S. Don’t forget to join the Electric Bike Report community for updates from the electric bike world, plus ebike riding and maintenance tips!